An SR would have either a PL or a B mount, both of which have a 52mm backfocus.

Most SLR's have lenses with backfocus in the 44-46mm range.

To use an unmodified lens, the adapter would have to hold the lens flange about 8mm inside the front plane of the camera body for the lens to reach infinity.

That's not to say it's not possible to use an SLR lens on a movie camera - this happens all the time. But the mount would have to be heavily modified, essentially, the mounting end of the lens comes off and new mount is fabricated.

This is why when you see an obvious SLR lens on a film camera it's often a telephoto - there's plenty of room behind the glass where nothing much is happening and modifying the mount is easy.